Handheld electronic device accessory



FIG. 1 is a three-quarter perspective view of a handheld electronic device accessory showing the new design;

FIG. 2 is a side view thereof, with views from all sides being the same;

FIG. 3 is a top view thereof; and,

FIG. 4 is a bottom view thereof.

The environmental features illustrated in broken lines in FIG. 1 form no part of the claimed design. 

The ornamental design for a handheld electronic device accessory, as shown and described. 